This invention relates to a pump, especially to a submersible pump.
In submersible pumps, the rotor is connected to the motor by a drive shaft surrounded by a first, internal, pipe in turn surrounded by a second, external, pipe. A seal is provided below a lowermost bearing, immediately adjacent to the rotor. The lowermost bearing is disposed in the internal pipe at a considerable distance from the rotor. Owing to this relatively large distance between the lowermost bearing and the rotor, the section of the drive shaft in that region at the end of the internal pipe is subjected to relatively large shocks. The seal, which generally takes the form of a slip ring seal, is also subjected to considerable stresses and can fail at an early time.
An object of the present invention is to provide an improved pump particularly of the submersible type.
Another, more particular, object of the present invention is to provide such a pump wherein a seal located in a region about a lowermost bearing is subjected to a minimum of wear and tear during pump operation.